Análise de região codificadora de rRNA de Lactobacillus delbrueckii UFV H2b20: Filogenia e presença de seqüência de inserção putativa

• Ano de defesa: 2003
• Autor(a) principal: Floresta, Fernanda Arruda
• Orientador(a): Moraes, Célia Alencar de
• Banca de defesa: Queiroz, Marisa Vieira de , Barros, Everaldo Gonçalves de , Tótola, Marcos Rogério , Passos, Flávia Maria Lopes
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Microbiologia Agrícola
• Departamento: Associações micorrízicas; Bactérias láticas e probióticos; Biologia molecular de fungos de interesse
• País: BR
• Palavras-chave em Português: Lactobacillus delbrueckii UFV H2b20; Identificação; Taxonomia; Análise filogenética; rDNA 16S; Seqüência de inserção putativa; Análise em gel de gradiente de desnaturação (DGGE)
• Palavras-chave em Inglês: Lactobacillus delbrueckii UFV H2b20; Identification; Taxonomy; Phylogenetic analysis; rDNA 16S; Putative Insertion Sequence; PCR-DGGE
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::MICROBIOLOGIA AGRICOLA
• Link de acesso: http://locus.ufv.br/handle/123456789/5295

Phylogenetic analysis of Lactobacillus UFV H2b20 based on the 16S rDNA sequence positions this isolate among the Lactobacillus delbrueckii subspecies. It confirms the classification by DNA/DNA hybridization. Comparisons of the substituted bases along the 16S rDNA sequence show that most are probably caused by 5-methylcytosine deamination that results in GC/AT transition. Presence of polymorphic copies of the 16S rRNA gene in Lactobacillus delbrueckii UFV H2b20 were confirmed by PCR-DGGE. Five distinct bands of rDNA amplified sequences confirm at least five different copies of the gene. The intensity of one of the bands allows the inference of two identical copies. The DGGE profile of this isolate was different from those of other L. delbrueckii strains, providing a mean to distinguish it in mixed cultures. Analysis of the nucleotide sequences along the rDNA region revealed the presence of putative insertion sequences. One of them, 915 bp long, was characterized and denominated ISLdH2b20. It presents a single ORF that encodes a putative transposase with some homology to the one of ISL5 of L. delbrueckii subsp. bulgaricus. All the characteristic elements of an IS were located as well as the putative regulatory sequences of the transposase.